In that video I actually preferred the 1x12 to the 2x12. I thought the 1x12 sounded closer to a "smaller" version of a 4x12 whereas the 2x12 here has a very exaggerated and ugly upper mid honk that the other two don't have.
Both the 2x12 and 1x12 sound like butthole to me. I’d be sad if any of my gear made those tones
I haven't tried them personally but I've never read of anyone being totally satisfied with those and other similar iso boxes. All accounts seem to indicate those enclosures create as many problems as they solve. The biggest complaint is this inherent and very pronounced boxiness that is simply an unavoidable byproduct of a very small enclosed space and the exaggerated reflections that the mic will pick up.
I had one many years ago. It was ok, but the mic attaching mechanism tended to rattle.
Yeah that was a thought that I had. I came across one on MF or maybe GC website a few months ago for just under $200 that had a v30 and an sm57 already in it. I passed because I didn't want a big useless box laying around if I didn't like it, and after doing the math after shipping + tax it came out to the same or more than a v30 and sm57 cost new if I ended up just salvaging those.
Shipping today would be a few bucks Im thinkin. Other bummer was only one mic in there. May be an issue for those that like more than one mic.
Never seen such a device. Is this supposed to be for studio or stage or both? Do metalheads forgo the room mic in the studio? I always like having a room mic, really adds depth and richness to the core SM57 sound.
Reading more about them later, they aren't really very quiet even stuffed into a closet. 
I had one of those 2x12 Avatar cabs. Liked it so much I bought the 4x12 version, great cab, will keep it forever. both with V30's though, actually the 4x12 originally came with v30/t75 in a X pattern, but I liked the more direct sound of all V30's. G12T75's are not for me.